Derivatives of acetals of polyhydric alcohols are useful in several applications, including for example as nucleating agents for polymer resins, and as gelling and thickening agents for organic liquids. Dibenzylidene sorbitol type (DBS) compounds are known for use in such applications.
The use of nucleating agents to reduce the haze in articles manufactured from crystalline polyolefin resins is known in the art. Representative acetals of sorbitol and xylitol, which have been employed as clarifying agents, are described in several patents, including for example: Hamada, et al., U.S. Pat. No. 4,016,118, dibenzylidene sorbitols; Kawai, et al., U.S. Pat. No. 4,314,039, di(alkylbenzylidene) sorbitols; Mahaffey, Jr., U.S. Pat. No. 4,371,645, di-acetals of sorbitol having at least one chlorine or bromine substituent; Kobayashi, et al., U.S. Pat. No. 4,954,291, distribution of diacetals of sorbitol and xylitol made from a mixture of dimethyl or trimethyl substituted benzaldehyde and unsubstituted benzaldehyde. Another reference, U.S. Pat. No. 5,049,605 to Rekers et al. discloses bis(3,4-dialkylbenzylidene) sorbitols, including substituents forming a carbocyclic ring.
Substitution of various groups upon the benzyl ring portion(s) of DBS-based compounds may have a significant impact upon the suitability of such compounds as nucleating or clarifying agents. A significant amount of work in the past has been directed to modifying the substitution of the benzylidene ring substituent(s). However, efforts still are underway to develop other compounds that are likely to afford reduced haze (and corresponding greater clarity) when used as plastic additives in polymer compositions.
The chemical arts often are unpredictable. Changing any portion or substituted group in these particular types of compounds may have a significant impact upon the performance and utility of the compound. This invention recognizes important new compositions that have not been known before, and may be quite useful as plastic additives, or as gelling agents, thickeners, or for other purposes.